1. Field of the Invention
The invention relates to a digital electrostatic printing machine having an ink applicator, a transfer cylinder, a central cylinder, and an electrostatically chargeable surface to which charging electrodes, a laser write head and a quench electrode are assigned.
2. Description of the Related Art
In principle such digital electrostatic printing machines already exist. The central unit of such digital electrostatic printing machines is a cylinder with an electrostatically chargeable surface (PIP cylinder). On the periphery of the cylinder the cylinder is statically charged with charging electrodes in a first station. Then a digital original is recorded by means of suitable software on the surface as the positive electrostatic pattern. In the next station, ink is transferred, according to this positive image, from the ink applicator to the cylinder. Then the ink is transferred onto the transfer cylinder and between transfer cylinder and central cylinder printed on the material to be printed. Behind the transfer cylinder the surface of the electrostatically chargeable cylinder is cleaned, before it is recharged with the suitably allocated charging electrodes.
In the case of this prior art digital electrostatic printing machine, the ink, to be transferred from the ink applicator, has to be transferred onto the image, which has been applied as a positive by the laser write head, at a high speed. However, there is the risk at high printing speeds that the applied ink will be blurred.